Dictionary.com
Thesaurus.com
Showing results for momentous. Search instead for jumentous.
Synonyms

momentous

American  
[moh-men-tuhs] / moʊˈmɛn təs /

adjective

  1. of great or far-reaching importance or consequence.

    a momentous day.

    Synonyms:
    serious, crucial, critical, vital
    Antonyms:
    trifling, trivial

momentous British  
/ məʊˈmɛntəs /

adjective

  1. of great significance

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See heavy.

Other Word Forms

Etymology

Origin of momentous

First recorded in 1645–55; moment + -ous

Explanation

Momentous describes an important event or moment in time. It is used for a time of great consequence or for a major accomplishment, and is almost always reserved for good things. When a moment is so great you know you'll never forget it, you have just experienced something momentous. It can be personal — perhaps the day you were named prom queen; or something historic — like the day Elizabeth was named Queen of England. Momentous and momentary share the root word moment but momentary describes just one fleeting moment in time. A momentary occurrence can certainly be momentous, but it's not always the case.

Keep Reading on Vocabulary.com

Vocabulary lists containing momentous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

As she approached the momentous milestone, Saar appeared more interested in creating new art than in dissecting her legacy.

From Los Angeles Times Jul. 27, 2026

This raises a momentous question: If diagnosed with a terminal illness, how can you weigh the decision in a calm, unhurried, fully informed manner?

From MarketWatch Jul. 20, 2026

Pope Leo XIV has called on European leaders to rise to the "momentous challenge" of handling migration as he visited the Italian island of Lampedusa.

From BBC Jul. 4, 2026

This week, Emily Bazelon, David Plotz, and guest host Ruth Marcus discuss this week’s momentous Supreme Court rulings.

From Slate Jul. 3, 2026

Nothing had happened—no momentous quarrel, no significant incident—rather, they had simply drifted apart, but it was Kainene who now anchored herself firmly in a distant place so that they could not drift back together.

From "Half of a Yellow Sun" by Chimamanda Ngozi Adichie

Vocabulary.com logo
by dictionary.com

Join 12,000,000 vocabulary learners

Start learning new words today on VocabTrainer.
You'll remember them forever.

Start training